Production of 6-amino-penicillanic acid sulfoxide



United States Patent U.S. Cl. 260306.7 3 Claims ABSTRACT OF THE DISCLOSURE A general procedure for the direct preparation of penicillin sulfoxides comprises the use of sodium metaperiodate in aqueous solution at pH 6.5-7.0 to produce the sulfoxides of 6-aminopenicillanic acid and seven penicillins.

This invention relates to an improved process for the production of penicillin sulfoxides and to the useful antibacterial agent and chemical intermediate 6-aminopenicillanic acid sulfoxide.

The sulfoxides of benzylpenicillin and phenoxymethylpenicillin have been prepared by a three-stage procedure comprising esterification of the carboxyl function followed by oxidation with sodium meta-periodate or hydrogen peroxide and subsequent removal of the protecting group by hydrogenolysis. It was the object of the present invention to provide a general procedure for the direct preparation of penicillin sulfoxides.

The object of the present invention was achieved by the provision, according to the present invention, of the proc- Patented Dec. 1, 1970 vention the useful chemical intermediate 6-aminopenicillanic acid sulfoxide.

The penicillin (or 6-aminopenicillanic acid) is used in the process of the present invention in the form of its free acid or of one of its water-soluble salts, e.g. sodium, potassium.

The following consolidated examples will serve to illustrate the present invention but not limit it as this is a general procedure.

General procedure for the preparation of penicillin sulfoxides A solution of the penicillin salt or free acid (0.10 mole) in the minimum volume of water at pH 7.5-8.0 was added to a solution of 23.5 g. (0.11 mole) of sodium meta-periodate (NaIO in 750 ml. of water. The pH of the mixture was adjusted to 6.5-7.0 and maintained at this value while the solution was stirred at room temperature for 2.5 hrs. The pH was then lowered to 2-2.5 by addition of phosphoric acid and the product was isolated as indicated in Table 1 below in one of the following three ways: (a) the precipitated sulfoxide was collected, thoroughly washed with cold water, dried by suction and recrystallized from an acetone-water mixture; (b) the gummy solid which separated was extracted into ethyl acetate, and the washed and dried extract was treated with a molar equivalent of a solution of either potassium or sodium Z-ethylhexanoate in n-butanol. The alkali metal salt thus precipitated was collected and recrystalized from an n-butanol-water-mixture; (c) the acidic aqueous solution was extracted with a solution of 600 ml. of methyl isobutyl ketone containing 33.3 g. (0.075 mole) of dioctyl sodium sulfosuccinate (Aerosol OT). The organic phase TABLE 1.PENICILLIN SULFOXIDES Percent Caled Found Yield, M.P., Isolation sulfoxide I Molecular formula percent C. (dec.) method 0 H C H Phenoxymethylpenicillin CmH N2OsS 76 178-180 (a) 52.45 4.95 52.66 5.18 5-rxrliethyl-iplieglyl-4-isoxazolylpenieillin (sodium salt- (C H1sNaN;OsS)2.H O 36 165-167 (b) 50.89 4.27 51.03 4.59

cm: y a e D}(11)1-;N(iahobenzyloxy-aminobenzylpenieillin- (C24H25N3O7S)z.HzO 52 133-135 (a) 56.70 5.16 56.25 .32

e y a e. D-()-a-aminobenzylpenicillin-dihydrate CmHmN O5S2H2O 25 210-212 (0) 47.88 5.78 48.15 5.78 fi-phthalimidopeuieillanic acid-hemihydrate. (C"H14NzOBS)z.H2O 35 160-162 (a) 51. 75 4.07 51.37 4. 22 fi-aminopenicillanic acid sesquihydrate (C3H12N204S)2-3H2O 8 248-250 (0) 37. 06 5.83 37.10 5. 57 6-Na-letarbobefi1zgloi33amino+pemcillanic acid (potassium CmHnKNzOaS-HzO 46 138. 5-140 (b) 45. 48 4. 53 45. 70 4. 28

s -mono y ae 6-triphenylmethylaminopenicillanie acid (potassium salt- (Cz7H25KN2O4S)2.H2O 88 213-215 (b) 62. 16 5. 03 62. 29 5. 06

hemihydrate) 1 A. W. Chow, N. M. Hall and .l'. R. E. Hoover, J. Org. Chem. 27, 1381 (1962).

E. Guddal, P. Morch and L. 'lybrlng, Tetrahedron Letters, N0. 9, 381 (1962).

was dried briefly over magnesium sulfate and then was treated dropwise with triethylamine to pH 5.0. The amorphous product which precipitated was collected and dried in vacuo.

6-arninopenicillanic acid sulfoxide and penicillin sulfoxides produced by the process of the present invention are effective antibacterial agents, especially versus Grampositive bacteria and are thus useful in the laboratory as applied, for example, to glassware to destroy contaminating organisms at concentrations in aqueous solution as low as -200 p.p.m.

6-aminopenicillanic acid sulfoxide and penicillin sulfoxides are particularly useful as chemical intermediates in the synthesis of cephalosporins as illustrated by the following reaction scheme, which is not part of my invention.

1. 0101120 0 cm L2. Acylate, e.g. with RC 0 01 0101110 0 N-Bromosuceinimide plus light and/or peroxide 1. CHaCOONa 2. CaHsSNfl G--ONa 3H ll 0 I claim: meta-periodate and then recovering the 6-aminopenicil- 1. 6-aminopenicillanic acid sulfoxide. 65 lanic acid sulfoxide produced thereby. 2. The process of producing 6-aminopenieillanic acid sulfoxide which comprises mixing in aqueous solution at References Cited about pH 6.5-7.0 and about 1040 lC. approximately UNITED STATES PATENTS equimolar amounts of 6-aminopenicil anic acid and an a 70 3,047,467 7/ 1962. Doyle et a1 260239.1 alkah metal meta-penodate and then recovering the 6 3,197,466 7/1965 Chow et a1 260 239 1 aminopenicillanic acid sulfoxide produced thereby.

3. The process of producing G-aminopem'cillanic acid NICHOLAS RIZZO Primary Examiner sulfoxide which comprises mixing in aqueous solution at about pH 6.5-7.0 and about 25 C. approximately equi- 75 US. Cl, X,R

molar amounts of fi-aminopenicillanic acid and sodium 260239.1, 243

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated December 1 1970 Patent No. 3 544 581 lnventofls) John M. Essery It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Table 1, line 2 of the Molecular formula column should read lg ls s e h' z Table 1, line 9 of Sulfoxide column should read 6-N-carbobenzyloxyamino -penicil1anic acid (potassium Signed and sealed this 20th day of April 1971.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JI

EDWARD M.FLETCHER,JR. Attesting Officer Commissioner of Patents 

